Rotating electric machine and cooling method thereof

ABSTRACT

A rotating electric machine having a plurality of ventilating passages formed between a stator frame and a stator iron core, a cooler which cools a coolant is provided at least in one ventilating passage, communicating with a central portion of the stator iron core, of the plurality of ventilating passages, and a ventilating circuit in which the coolant cooled by the cooler is allowed to flow to the central portion of the stator iron core in a direction from an outer peripheral side to an inner peripheral side of the stator iron core via the at least one ventilating passage which communicates with the central portion of the stator iron core.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This is a continuation of U.S. application Ser. No. 09/509,768,filed Mar. 31, 2000, the subject matter of which is incorporated byreference herein.

TECHNICAL FIELD

[0002] The present invention relates to a rotating electric machine inwhich a cooler for cooling a coolant is provided, as well as to a methodof cooling a rotating electric vehicle.

BACKGROUND OF THE INVENTION

[0003] A rotating electric machine in which a cooler for cooling acoolant is provided has been described, for example, in Japanese PatentLaid-open Nos. Hei 7-177705 and Hei 10-146022. The rotating electricmachine described in these documents is configured such that a spacebetween a stator frame and a stator iron core is partitioned into a lowtemperature gas chamber, to which a coolant at a low temperature issupplied, and a high temperature gas chamber, in which the heatedcoolant flows. A plurality of coolers distributed in the axial directionare provided in a foundation pit under the rotating electric machine,whereby the coolant cooled by the plurality of coolers and boosted by aventilating fan is introduced to various heat sources, such as the ironcore and the coils, via the low temperature gas chamber, and the coolantwhich has been used for cooling the heat sources is returned to thecoolers via the high temperature gas chamber.

[0004] The above-described rotating electric machine, however, has aproblem. Since the coolant which has passed through one or two or moreof the heat sources is then introduced to a central portion of the ironcore, the temperature of the coolant is raised before the coolantreaches the central portion of the iron core. Accordingly, for theabove-described rotating electric machine, if a thermal load generatedfrom the heat sources, such as the iron core and coils, becomes largewith an increase in the generation capacity or in the loss density, thecooling effect of the coolant introduced to the central portion of theiron core is significantly degraded. As a result, in the above-describedrotating electric machine, there is a possibility that local heatgeneration will occur in a gap between the stator iron core and a rotoriron core, thereby to increase the thermal oscillation stroke of therotor due to uneven thermal expansion of the rotor in the axialdirection.

[0005] To solve the above-described problem, there may be considered amethod of increasing the amount of the coolant or optimizing thedistribution of the amounts of the coolant components supplied torespective ventilating passages by adjusting the ventilating resistance;however, according to the former method, the ventilation loss of thecoolant caused upon boosting the coolant by the fan becomes larger, toincrease the total loss in the coolant; and, according to the lattermethod, since the ventilation resistance must be adjusted while thedesired electric and mechanical characteristics are satisfied in alimited space, it is difficult to optimize the distribution of thecoolant components supplied to the respective ventilating passages.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a rotatingelectric machine which is capable of exhibiting a level axialtemperature rise distribution, and a cooling method thereof.

[0007] The basic feature of the present invention is to supply acoolant, which is sufficiently cooled, to a central portion of an ironcore which is most distant from both axial ends of the iron core. Torealize this feature of the present invention, a plurality ofventilating passages, which continuously extend in the peripheraldirection, are provided in the axial direction between a stator frameand a stator iron core, and coolers are provided in at least thosepassages, which communicate with the central portion of the iron core,of the plurality of ventilating passages formed in the axial direction,wherein the coolant boosted by a booster is cooled by the coolers and isallowed to flow to the central portion of the iron core in the directionfrom the outer peripheral side to the inner peripheral side of the ironcore via the ventilating passages.

[0008] If an even number of ventilating passages are provided, two tofour of the ventilating passages, which are located on the central side,constitute the ventilating passages which communicate with the centralportion of the iron core. If an odd number of ventilating passages areprovided, one to three of the ventilating passages, which are located onthe central side, constitute the ventilating passages which communicatewith the central portion of the iron core. The number of the ventilatingpassages is dependent on the capacity of the rotating electric machine.For example, for a generator having a generation capacity of 100 MWclass, at least three ventilating passages are provided, and for agenerator having a generation capacity of 350 MW class or more, seven toten or more ventilating passages are provided.

[0009] According to the above feature of the present invention, it ispossible to level the axial temperature rise distribution in themachine. In particular, the above feature is effective in a rotatingelectric machine in which the axial length is long and air is used as acoolant, for example, an air-cooled generator having a large capacity.Air which is larger in viscosity than hydrogen exhibits a highventilating resistance when it flows in a generator, to thereby cause atemperature rise. The longer the ventilating distance of air, the largerthe ventilating resistance will be. As a result, for a generator whichis longer in axial length and larger in capacity, the temperature riseof the air becomes significantly larger, and the amount of the airsupplied to the central portion of an iron core becomes smaller.

[0010] Accordingly, a small amount of air whose temperature is raised issupplied to the central portion of the iron core which is most distantfrom both the axial ends of the iron core, with a result that thereoccurs a difference in temperature between each of the axial ends of theiron core and the central portion of the iron core. According to thepresent invention, it is possible to supply a coolant which issufficiently cooled to the central portion of the iron core, however, itis also possible to suppress the temperature rise of the central portionof the iron core to an allowable value or less, and, hence, to level theaxial temperature rise distribution in the machine.

[0011] The leveling of the axial temperature rise distribution in themachine means that the temperature rise of the central portion of theiron core is suppressed to an allowable value or less, to reduce thedifference in temperature between each of the axial ends of the ironcore and the central portion of the iron core. Accordingly, there is novariation in the axial temperature rise distribution in the machine.

BRIEF DESCRIPTION OF DRAWINGS

[0012]FIG. 1 is a perspective view, with parts partially cutaway,showing the external appearance and inner configuration of a turbinegenerator according to a first embodiment of the present invention;

[0013]FIG. 2 is a plan view, as seen in the direction shown by an arrowII of FIG. 1, showing the external configuration of the turbinegenerator;

[0014]FIG. 3 is a plan view, as seen in the direction shown by an arrowIII of FIG. 2, showing the external configuration of the turbinegenerator;

[0015]FIG. 4 is a sectional view taken on line IV-IV of FIG. 1, showingthe inner structure of a portion, positioned under a rotating shaft, ofthe turbine generator;

[0016]FIG. 5 is a perspective view showing the external configuration ofa turbine generator according to a second embodiment of the presentinvention;

[0017]FIG. 6 is a sectional view taken on line VI-VI of FIG. 5, showingthe inner structure of a portion, positioned over a rotating shaft, ofthe turbine generator;

[0018]FIG. 7 is a sectional view showing the inner structure of aportion, positioned over a rotating shaft, of a turbine generatoraccording to a third embodiment;

[0019]FIG. 8 is a sectional view showing the inner structure of aportion, positioned over a rotating shaft, of a turbine generatoraccording to a fourth embodiment of the present invention;

[0020]FIG. 9 is a sectional view showing the inner structure of aportion, positioned under a rotating shaft, of a turbine generatoraccording to a fifth embodiment of the present invention;

[0021]FIG. 10 is a front view showing the external configuration of aturbine generator according to a sixth embodiment of the presentinvention;

[0022]FIG. 11 is a side view, as seen in the direction shown by an arrowXI of FIG. 10, showing the external configuration of the turbinegenerator;

[0023]FIG. 12 is a sectional top view taken on line XII-XII of FIG. 11,showing the inner configuration of the turbine generator;

[0024]FIG. 13 is a sectional view showing the inner configuration of aportion, positioned under a rotating shaft, of a turbine generatoraccording to a seventh embodiment of the present invention; and

[0025]FIG. 14 is a sectional view showing the inner configuration of aportion, positioned under a rotating shaft, of a turbine generatoraccording to an eighth embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0026] Hereinafter, various embodiments of the present invention will bedescribed with reference to the drawings.

[0027] (First Embodiment)

[0028] FIGS. 1 to 4 show the configuration of a turbine generatoraccording to a first embodiment of the present invention. The turbinegenerator in this embodiment is of an enclosed type (or a full-closedtype) in which the inside of the generator is cooled with a coolantenclosed in the generator. In these figures, reference numeral 1designates a stator frame. A cylindrical stator iron core 2 is providedinside the stator frame 1. A plurality of slots 3, which continuouslyextend in the axial direction, are formed in an inner peripheral portionof the stator iron core 2 in such a manner as to extend in theperipheral direction. Stator coils 4 are enclosed in the slots 3. Aplurality of ventilating ducts 5, which continuously extending theradial direction, are formed in the stator iron core 2 in such a manneras to be spaced from each other at equal intervals in the axialdirection.

[0029] A rotor iron core 7 is provided on the inner peripheral side ofthe stator iron core 2 and is disposed with an air gap 6 between therotor iron core 7 and the stator iron core 2. A plurality of slots (notshown), which continuously extend in the axial direction, are formed inan outer peripheral portion of the rotor iron core 7 in such a manner asto extend in the peripheral direction. Rotor coils (not shown) areenclosed in the slots of the rotor iron core 7. Cylindrical retainingrings 8 for pressing both ends of the rotor coils are provided at bothends of the rotor iron core 7. A rotating shaft 9 is provided integrallywith the rotor iron core 7 in such a manner as to extend in the axialdirection along the central axis of the rotor iron core 7.

[0030] Annular end brackets 10 functioning as block members are providedat both axial ends of the stator frame 1. A bearing apparatus 11 forrotatably supporting the rotating shaft 9 is provided on the innerperipheral side of each end bracket 10.

[0031] A current collector 12 for supplying power to the rotor coilsduring rotation is provided at one end (outside the bearing apparatus11) of the rotating shaft 9. The current collector 12 is configured toelectrically connect the stator side to the rotor side by bringingcarbon brushes into press-contact with a current-collecting ringprovided at the one end (outside the bearing apparatus 11) of therotating shaft 9. A connecting portion connected to a turbine, servingas a driving source for rotating the generator, is formed at the otherend (outside the bearing apparatus 11) of the rotating shaft 9.

[0032] Fans 13 for boosting a coolant enclosed in the generator andcirculating it in the generator are provided at both ends (inside thebearing apparatuses 11) of the rotating shaft 9. While the fans 13 areused as boosters for boosting the coolant in this embodiment, othertypes of boosters may be used. The fans 13 provided at both ends(outside the bearing apparatuses 11) of the rotating shaft 9 areright-left symmetrical with respect to a center line 14. The center line14 is a bisector which crosses the rotating shaft 9 at right angles atsuch a position as to equally divide the distance between the endbrackets 10 into right-left symmetric parts.

[0033] Terminals 15 for three-phases of voltage are provided on theupper surface of the stator frame 1 in such a manner as to projectupwardly therefrom. The terminals 15 are used for taking generated powerout of the stator coils 4, which are electrically connected to theterminals 15. Hoisting accessories 16 are provided on the front surfaceof the stator frame 1 at two positions and on the back surface thereofat two positions. For example, when installed in a foundation pit 17,the generator main body is hoisted by a crane via wires fastened to thehoisting accessories 16.

[0034] Ventilating passages 18 a to 18 g, which continuously extend inthe peripheral direction, are provided between the stator frame 1 andthe stator iron core 2 in parallel to each other in the axial direction.The ventilating passages 18 a to 18 g are formed by a plurality ofannular partition plates 19 for partitioning the space between thestator frame 1 and the stator iron core 2 in the axial direction, theinner surface of the stator frame 1, and the outer peripheral surface ofthe stator iron core 2, and they communicate with the ventilating ducts5 in the stator iron core 2. The ventilating passages 18 a to 18 g areright-left symmetrical with respect to the center line 14.

[0035] Ventilating ducts 22 a to 22 c, extending in the axial direction,are provided on the back surface of the stator frame 1 in parallel witheach other in a direction perpendicular to the axial direction. Theventilating ducts 22 a and 22 c form ventilating passages 20continuously extending in the axial direction. The ventilating passages20 communicate with the ventilating passages 18 b, 18 d, and 18 f. Theventilating duct 22 b forms a ventilating passage 21 continuouslyextending in the axial direction. The ventilating passage 21communicates with the ventilating passages 18 a, 18 c, 18 e, and 18 g.

[0036] Ventilating passages 23 to 26, which continuously extend in theradial direction, are provided between the stator iron core 2 and theend brackets 10. The ventilating passages 23 to 26 are formed bypartitioning a space between the stator iron core 2 and the end bracket10 annular partitioning plates 27 facing the outer peripheral side ofthe fan 13. The ventilating passages 23 and 24, each of which providescommunication between the discharge side of the fan 13 and theventilating passage 20, are right-left symmetrical with respect to thecenter line 14. The ventilating passages 25 and 26, each of whichprovides communication between the suction side of the fan 13 and theventilating passage 21, are right-left symmetrical with respect to thecenter line 14.

[0037] Each of the ventilating passages 18 a to 18 g is provided with acooler for cooling a coolant enclosed in the generator. The coolers 28 ato 28 g are arranged under the generator in such a manner as to bealigned in a row in the axial direction. It should be noted that thecoolers 28 a to 28 g also may be arranged on the upper portion of thegenerator. The coolers 28 a to 28 g are disposed so as to be right-leftsymmetrical with respect to the center line 14. A pipe line 29 forsupplying cooling water and a pipe line 30 for discharging cooling waterare connected to each of the coolers 28 a to 28 g. The coolers 28 a to28 g are identical to each other in cooling capacity, but are differentfrom each other in external size depending on the size of theventilating passage 18 on which the cooler is provided. In thisembodiment, since the axial width of each of the ventilating passages 18b and 18 f is smaller than that of each of the remaining ventilatingpassages, the axial width of each of the coolers 28 b and 28 f is madesmaller than that of each of the remaining coolers.

[0038] A plurality of ventilating circuits configured by theabove-described ventilating passages, etc. are formed in the generator.A first ventilating circuit 29, a second ventilating circuit 30, and athird ventilating circuit 31 are formed on one side (left side in FIG.4) the center line 14, and similarly three ventilating circuits areformed on the other side (right side in FIG. 4) relative to the centerline 14. The three ventilating circuits formed on the one side from thecenter line 14 are right-left symmetrical relative to the threeventilating circuits formed on the other side from the center line 14.Further, the flow of a coolant and the temperature rise characteristicon the one side from the center line 14 are right-left symmetricalrelative to those on the other side from the center line 14. Therefore,the configuration of the ventilating circuits and the flow of a coolanton only one side of the center line 14 will be described below.

[0039] The first ventilating circuit 29 is a closed loop designated by asolid arrow in FIG. 4, which extends from the discharge side of the fan13 to the ventilating duct 5 via the air gap 6, further extends from theventilating duct 5 to the cooler 28 a via the ventilating passage 18 a,and then extends from the cooler 28 a to the suction side of the fan 13via the ventilating passages 21 and 25. In the first ventilating circuit29, heat sources giving heat to the ventilating passages 18 a, air gap 6and ventilating duct 5 are connected in series to the cooler 28 a. Theheat source giving heat to the air gap 6 and the ventilating passage 18a is the stator iron core 2 generating iron loss, and the heat sourcesgiving heat to the ventilating duct 5 are the stator iron core 2generating iron loss and the stator coils 4 generating copper loss.

[0040] The second ventilating circuit 30 is a closed loop designated bya dotted arrow in FIG. 4, which extends from the discharge side of thefan 13 to the cooler 28 b via the ventilating passage 23, furtherextends from the cooler 28 b to the cooler 28 c via the ventilatingpassage 18 b, ventilating duct 5, air gap 6, ventilating duct 5, andthen ventilating passage 18 c, and extends from the cooler 28 c to thesuction side of the fan 13 via the ventilating passages 21 and 25. Inthe second ventilating circuit 30, heat sources and the coolers arealternately arranged in series, and, more specifically, the heat sourcesgiving heat to the ventilating passage 23, the cooler 28 b, the heatsources giving heat to the ventilating passages 18 b and 18 c, air gap 6and ventilating duct 5, and the cooler 28 c are arranged in this order.The heat source giving heat to the air gap 6 and ventilating passages 18b and 18 c is the stator iron core 2 generating iron loss, and the heatsources giving heat to the ventilating duct 5 and the ventilatingpassage 23 are the stator iron core 2 generating iron loss and thestator coils 4 generating copper loss.

[0041] The third ventilating circuit 31 is a closed loop designated by adotted arrow in FIG. 4, which extends from the discharge side of the fan13 to the cooler 28 d via the ventilating passage 23, further extendsfrom the cooler 28 d to the cooler 28 c via the ventilating passage 18d, ventilating duct 5, air gap 6, ventilating duct 5, and ventilatingpassage 18 c, and then extends from the cooler 28 c to the suction sideof the fan 13 via the ventilating passages 21 and 25. In the secondventilating circuit 30, heat sources and the coolers are alternatelyarranged in series, and more specifically, the heat sources giving heatto the ventilating passage 23, the cooler 28 d, the heat sources givingheat to the ventilating passages 18 d and 18 c, air gap 6, andventilating duct 5, and the cooler 28 c are arranged in series in thisorder. The heat source giving heat to the air gap 6 and the ventilatingpassages 18 d and 18 c is the stator iron core 2 generating iron loss,and the heat sources giving heat to the ventilating duct 5 and theventilating passage 23 are the stator iron core 2 generating iron lossand the stator coils 4 generating copper loss.

[0042] The flow of the coolant will be described below. The coolantenclosed in the generator, which is boosted by rotation of the rotatingshaft 9, flows from the discharge side of the fan 13 to each ventilatingcircuit. In the ventilating circuit 29, the coolant boosted by the fan13 flows axially in the air gap 6 to the ventilating duct 5communicating with the ventilating passage 18 a. The coolant which hasreached the ventilating duct 5 communicating with the ventilating duct18 a flows in the ventilating duct 5 from the inner peripheral side tothe outer peripheral side of the stator iron core 2, that is, to theventilating passage 18 a while cooling the inside of the stator ironcore 2 and the stator coils 4. The coolant which has reached theventilating passage 18 a cools the outer peripheral side of the statoriron core 2 and flows in the ventilating passage 18 a to the cooler 28a. The coolant which has reached the cooler 28 a is cooled by the cooler28 a and flows from the cooler 28 a to the suction side of the fan 13via the ventilating passages 21 and 25.

[0043] In the second ventilating circuit 30, the coolant boosted by thefan 13 flows radially in the ventilating passage 23 to the ventilatingpassage 20 while cooling the end portion of the stator iron core 2 andthe coil end portions of the stator coils 4. The coolant which hasreached the ventilating passage 20 flows axially in the ventilatingpassage 20 to the cooler 28 b. The coolant which has reached the cooler28 b is cooled by the cooler 28 b and flows in the ventilating passage18 b in the peripheral direction while cooling the outer peripheralportion of the stator iron core 2 and reaches the ventilating duct 5communicating with the ventilating passage 18 b. The coolant which hasreached the ventilating duct 5 communicating with the ventilatingpassage 18 b flows in the ventilating duct 5 from the outer peripheralside to the inner peripheral side of the stator iron core 2, that is, tothe air gap 6 while cooling the inside of the stator iron core 2 and thestator coils 4.

[0044] The coolant which has reached the air gap 6 flows axially in theair gap 6 to the ventilating duct 5 communicating with the ventilatingpassage 18 c while cooling the inner peripheral side of the stator ironcore 2. The coolant which has reached the ventilating duct 5communicating with the ventilating passage 18 c flows in the ventilatingduct 5 from the inner peripheral side to the outer peripheral side ofthe stator iron core 2, that is, to the ventilating passage 18 c whilecooling the inside of the stator iron core 2 and the stator coils 4. Thecoolant which has reached the ventilating passage 18 c cools the outerperipheral side of the stator iron core 2 and flows in the ventilatingpassage 18 c to the cooler 28 c. The coolant which has reached thecooler 28 c is cooled by the cooler 28 c, and flows from the cooler 28 cto the suction side of the fan 13 via the ventilating passages 21 and25.

[0045] In the third ventilating circuit 31, the coolant boosted by thefan 13 flows radially in the ventilating passage 23 to the ventilatingpassage 20 while cooling the end portion of the stator iron core 2 andthe coil end portions of the stator coils 4. The coolant which hasreached the ventilating passage 20 flows axially in the ventilatingpassage 20 to the cooler 28 d. The coolant which has reached the cooler28 d is cooled by the cooler 28 d and flows in the ventilating passage18 d in the peripheral direction while cooling the outer peripheral sideof the stator iron core 2 and reaches the ventilating duct 5communicating with the ventilating passage 18 d. The coolant which hasreached the ventilating duct 5 communicating with the ventilatingpassage 18 d flows in the ventilating duct 5 from the outer peripheralside to the inner peripheral side of the stator iron core 2, that is, tothe air gap 6 while cooling the inside of the stator iron core 2 and thestator coils 4.

[0046] The coolant which has reached the air gap 6 flows axially in theair gap to the ventilating duct 5 communicating with the ventilatingpassage 18 c while cooling the inner peripheral side of the stator ironcore 2. The coolant which has reached the ventilating duct 5communicating with the ventilating passage 18 c flows in the ventilatingduct 5 from the inner peripheral side to the outer peripheral side ofthe stator iron core 2, that is, to the ventilating passage 18 c whilecooling the inside of the stator iron core 2 and the stator coils 4. Thecoolant which has reached the ventilating passage 18 c cools the outerperipheral side of the stator iron core 2 and flows in the ventilatingpassage 18 c to the cooler 28 c. The coolant which has reached thecooler 28 c is cooled by the cooler 28 c, and flows from the cooler 28 cto the suction side of the fan 13 via the ventilating passages 21 and25.

[0047] According to the embodiment configured as described above, thecoolant boosted by the fan 13 is introduced to the ventilating passage18 d positioned at the central portion of the stator iron core 2, beingcooled by the cooler 28 d, and is allowed to flow from the outerperipheral side to the inner peripheral side of the stator iron core 2,so that the coolant sufficiently cooled by the cooler can be supplied tothe central portion of the stator iron core 2.

[0048] Accordingly, the central portion of the stator iron core 2 atwhich the temperature of the supplied coolant tends to become highestand the amount of the supplied coolant tends to become smallest can becooled by the coolant, which is sufficiently cooled by the cooler, andthereby local heat generation in the air gap 6 can be suppressed. Thismakes it possible to level the axial temperature rise distribution inthe generator and hence to suppress the thermal oscillation stroke ofthe rotor.

[0049] (Second Embodiment)

[0050]FIGS. 5 and 6 show a configuration of a turbine generatoraccording to a second embodiment. The turbine generator in thisembodiment is of an enclosed type (or a full-closed type) like theturbine generator in the first embodiment, but is shorter in axiallength (or smaller in generation capacity) than the turbine generator inthe first embodiment. Further, the turbine generator in this embodimentis configured such that the coolers 28 and the ventilating passages 20and 21 provided in the lower portion of the generator in the firstembodiment are provided in an upper portion of the generator.

[0051] Ventilating passages 18 a to 18 d, which continuously extend inthe peripheral direction, are provided between a stator frame 1 and astator iron core 2 in parallel with each other in the axial direction.The ventilating passages 18 b and 18 c are in communication with aventilating passage 20, and the ventilating passages 18 a and 18 d arein communication with a ventilating passage 21. Coolers 28 a and 28 dare provided in the ventilating passage 21 in such a manner as to beright-left symmetrical with respect to a center line 14, and coolers 28b and 28 c are provided in the ventilating passage 20 in such a manneras to be right-left symmetrical with respect to the center line 14. Thecoolers 28 a to 28 d are aligned in a row in the axial direction.

[0052] The coolers 28 b and 28 c are smaller in size, that is, have asmaller cooling capacity than the coolers 28 a and 28 d. One reason forthis is that the coolers 28 b and 28 c are used for cooling part of acoolant which has been cooled by the coolers 28 a and 28 d, andtherefore, it is sufficient for the coolers 28 b and 28 c to be smallerin cooling capacity than the coolers 28 a and 28 d. This is advantageousin terms of cooling efficiency. Another reason is that, since theventilating passage 20 in which the coolers 28 b and 28 c are providedis smaller than the ventilating passage 21 in which the coolers 28 a and28 d are provided, the sizes of the coolers 28 b and 28 c must be madesmaller those of the coolers 28 a and 28 d. It should be noted that thecoolers 28 a to 28 d may be arranged in the lower portion of thegenerator.

[0053] The other features of this embodiment are the same as those ofthe first embodiment, and therefore, a description thereof is omitted.In addition, since the ventilating passages and coolers are respectivelyright-left symmetrical with respect to the center line 14, and also theflow of a coolant and the temperature rise characteristic arerespectively right-left symmetrical with respect to the center line 14,the configuration on only one side of the center line 14 will bedescribed below.

[0054] The flow of a coolant will be described. When a fan 13 is rotatedalong with rotation of a rotating shaft 9, a coolant enclosed in thegenerator is boosted and is allowed to flow in respective ventilatingpassages. The coolant discharged on the discharge side of the fan 13 isbranched into one component on a ventilating passage 23 side and anothercomponent on an air gap 6 side. The coolant component branched on theair gap 6 side flows in an air gap 6 to a ventilating duct 5communicating with the ventilating passage 18 a while cooling the innerperipheral side of the stator iron core 2.

[0055] The coolant component which has reached the ventilating duct 5communicating with the ventilating passage 18 a flows in the ventilatingduct 5 from the inner peripheral side to the outer peripheral side ofthe stator iron core 2, that is, to the ventilating passage 18 a whilecooling the inside of the stator iron core 2 and stator coils 4. Thecoolant component which has reached the ventilating passage 18 a coolsthe outer peripheral side of the stator iron core 2 and flows from theventilating passage 18 a to the cooler 28 a via the ventilating passage21. The coolant component which has reached the cooler 28 a is cooled bythe cooler 28 a and flows from the cooler 28 a to the suction side ofthe fan 13 via the ventilating passage 25.

[0056] The coolant component branched on the ventilating passage 23 sideflows radially in a ventilating passage 23 to the ventilating passage 20while cooling the end portion of the stator iron core 2 and the coil endportions of the stator coils 4. The coolant component which has reachedthe ventilating passage 20 flows axially in the ventilating passage 20to the cooler 28 b. The coolant component which has reached the cooler28 b is cooled by the cooler 28 b, and flows from the cooler 28 b to theventilating passage 18 b. The coolant component which has reached theventilating passage 18 b cools the outer peripheral side of the statoriron core 2, and flows in the ventilating passage 18 b to theventilating duct 5 communicating with the ventilating passage 18 b.

[0057] The coolant component which has reached the ventilating duct 5communicating with the ventilating passage 18 b flows in the ventilatingduct 5 from the outer peripheral side to the inner peripheral side ofthe stator iron core 2, that is, to the air gap 6 while cooling theinside of the stator iron core 2 and the stator coils 4. The coolantcomponent which has reached the air gap 6 flows axially in the air gap 6to the ventilating duct 5 communicating with the ventilating passage 18a while cooling the inner peripheral side of the stator iron core 2. Thecoolant component which has reached the ventilating duct 5 communicatingwith the ventilating passage 18 a flows in the ventilating ducts 5together with the above-described coolant component which has beenbranched from the discharge side of the fan 13 onto the air gap 6 side.

[0058] According to this embodiment, part of the coolant cooled by thecooler 28 a (or 28 d) and boosted by the fan 13 is branched; and, thecoolant component thus branched is cooled by the cooler 28 b (or 28 c),being introduced to the ventilating passage 18 b (or 18 c) positioned atthe central portion of the stator iron core 2, and is allowed to flowfrom the outer peripheral side to the inner peripheral side of thestator iron core 2. Accordingly, it is possible to supply the coolantsufficiently cooled by the cooler, to the central portion in the axialdirection of the stator iron core 2.

[0059] As a result, according to this embodiment, the central portion ofthe stator iron core 2 at which the temperature of the supplied coolanttends to become highest and the amount of the supplied coolant tends tobecome smallest can be cooled by the coolant, which is sufficientlycooled by the cooler, so that it is possible to suppress local heatgeneration in the air gap 6, and hence to level the axial temperaturerise distribution in the generator.

[0060] (Third Embodiment)

[0061]FIG. 7 shows a configuration of a turbine generator according to athird embodiment. This embodiment is a variation of the secondembodiment, characterized in that the axial length of the turbinegenerator in this embodiment is longer than that of the turbinegenerator in the second embodiment. Ventilating passages 18 a to 18 e,which continuously extend in the peripheral direction, are providedbetween a stator frame 1 and a stator iron core 2 in parallel to eachother in the axial direction. The ventilating passages 18 a, 18 b, 18 dand 18 e are in communication with a ventilating passage 21, and theventilating passage 18 c is in communication with a ventilating passage20. Coolers 28 a and 28 c are provided in the ventilating passage 21 insuch a manner as to be right-left symmetrical with respect to a centerline 14, and a cooler 28 b is provided in the ventilating passage 20 ata communicating portion communicating with the ventilating passage 18 c.The cooler 28 b is smaller in size or cooling capacity than each of thecoolers 28 a and 28 c.

[0062] The other features of this embodiment are the same as those ofthe second embodiment, and, therefore, a description thereof is omitted.In addition, since the ventilating passages and coolers are respectivelyright-left symmetrical with respect to the center line 14, and also theflow of coolant and the temperature rise characteristic are respectivelyright-left symmetrical with respect to the center line 14, theconfiguration on only one side of the center line 14 will be describedbelow.

[0063] The flow of a coolant will be described. When a fan 13 is rotatedalong with rotation of a rotating shaft 9, a coolant enclosed in thegenerator is boosted and is allowed to flow in respective ventilatingpassages. The coolant discharged on the discharge side of the fan 13 isbranched into one component on a ventilating passage 23 side and anothercomponent on an air gap 6 side. The coolant component branched on theair gap 6 side flows in an air gap 6 to ventilating ducts 5communicating with the ventilating passages 18 a and 18 b while coolingthe inner peripheral side of the stator iron core 2.

[0064] The coolant component which has reached the ventilating ducts 5communicating with the ventilating passages 18 a and 18 b flows in theventilating ducts 5 from the inner peripheral side to the outerperipheral side of the stator iron core 2, that is, to the ventilatingpassages 18 a and 18 b, while cooling the inside of the stator iron core2 and stator coils 4. The coolant component which has reached theventilating passages 18 a and 18 b cools the outer peripheral side ofthe stator iron core 2 and flows from the ventilating passages 18 a and18 b to the cooler 28 a via the ventilating passage 21. The coolantcomponent which has reached the cooler 28 a is cooled by the cooler 28 aand flows from the cooler 28 a to the suction side of the fan 13 via aventilating passage 25.

[0065] The coolant component branched on the ventilating passage 23 sideflows radially in a ventilating passage 23 to the ventilating passage20, while cooling the end portion of the stator iron core 2 and the coilend portions of the stator coils 4. The coolant component which hasreached the ventilating passage 20 flows axially in the ventilatingpassage 20 to the cooler 28 b. The coolant component which has reachedthe cooler 28 b is cooled by the cooler 28 b, and flows from the cooler28 b to the ventilating passage 18 c. The coolant component which hasreached the ventilating passage 18 c cools the outer peripheral side ofthe stator iron core 2 and flows in the ventilating passage 18 c to theventilating duct 5 communicating with the ventilating passage 18 c.

[0066] The coolant component which has reached the ventilating duct 5communicating with ventilating passage 18 c flows in the ventilatingduct 5 from the outer peripheral side to the inner peripheral side ofthe stator iron core 2, that is, to the air gap 6, while cooling theinside of the stator iron core 2 and the stator coils 4. The coolantcomponent which has reached the air gap 6 flows axially in the air gap 6to the ventilating ducts 5 communicating with the ventilating passages18 a and 18 b, while cooling the inner peripheral side of the statoriron core 2. The coolant component which has reached the ventilatingducts 5 communicating with the ventilating passages 18 a and 18 b flowsin the ventilating ducts 5 together with the above-described coolantcomponent which has been branched from the discharge side of the fan 13onto the air gap 6 side.

[0067] According to this embodiment, part of the coolant cooled by thecooler 28 a (or 28 c) and boosted by the fan 13 is branched; and, thecoolant component thus branched is cooled by the cooler 28 c, beingintroduced to the ventilating passage 18 c positioned at the centralportion of the stator iron core 2, and is allowed to flow from the outerperipheral side to the inner peripheral side of the stator iron core 2.

[0068] Accordingly, it is possible to supply the coolant, which issufficiently cooled by the cooler, to the central portion of the statoriron core 2.

[0069] As a result, according to this embodiment, the central portion ofthe stator iron core 2, at which the temperature of the supplied coolanttends to become highest and the amount of the supplied coolant tends tobecome smallest, can be cooled by the coolant, which is sufficientlycooled by the cooler, so that it is possible to suppress local heatgeneration in the air gap 6, and hence to level the axial temperaturerise distribution in the generator.

[0070] (Fourth Embodiment)

[0071]FIG. 8 shows a configuration of a turbine generator according to afourth embodiment. This embodiment is a combination of the second andthird embodiments, characterized in that the axial length of the turbinegenerator in this embodiment is longer than that of the turbinegenerator in the third embodiment. Ventilating passages 18 a to 18 g,which continuously extend in the peripheral direction, are providedbetween a stator frame 1 and a stator iron core 2 in parallel to eachother in the axial direction. The ventilating passages 18 a, 18 c, 18 eand 18 g are in communication with a ventilating passage 21, and theventilating passage 18 d is in communication with a ventilating passage20. A ventilating passage 31 for connecting a ventilating passage 23 tothe ventilating passage 18 b and a ventilating passage 32 for connectinga ventilating passage 24 to the ventilating passage 18 f are providedbetween the stator frame 1 and the stator iron core 2 in such a manneras to be right-left symmetrical with respect to a center line 14.

[0072] Coolers 28 a and 28 e are provided in the ventilating passage 21in such a manner as to be right-left symmetrical with respect to thecenter line 14. A cooler 28 c is with provided in the ventilatingpassage 20 at a portion communicating with the ventilating passage 18 d.The cooler 28 c is smaller in size or cooling capacity than each of thecoolers 28 a and 28 e. Coolers 28 b and 28 d are provided in theventilating passage 31 in such a manner as to be right-left symmetricalwith respect to the center line 14. The coolers 28 b and 28 d are eachsmaller in size or cooling capacity than each of the coolers 28 a and 28e.

[0073] The other features of this embodiment are the same as those ofeach of the second and third embodiments, and, therefore, a descriptionthereof is omitted. In addition, since the ventilating passages andcoolers are respectively right-left symmetrical with respect to thecenter line 14, and also the flow of a coolant and the temperature risecharacteristic are respectively right-left symmetrical with respect tothe center line 14, the configuration on only one side of the centerline 14 will be described below.

[0074] The flow of a coolant will be described. When a fan 13 is rotatedalong with rotation of a rotating shaft 9, a coolant enclosed in thegenerator is boosted and is allowed to flow in respective ventilatingpassages. The coolant discharged on the discharge side of the fan 13 isbranched into one component on a ventilating passage 23 side and anothercomponent on an air gap 6 side. The coolant component branched on theair gap 6 side flows in an air gap 6 to ventilating ducts 5communicating with the ventilating passages 18 a and 18 c while coolingthe inner peripheral side of the stator iron core 2.

[0075] The coolant component which has reached the ventilating ducts 5communicating with the ventilating passages 18 a and 18 c flows in theventilating ducts 5 from the inner peripheral side to the outerperipheral side of the stator iron core 2, that is, to the ventilatingpassages 18 a and 18 c, while cooling the inside of the stator iron core2 and stator coils 4. The coolant component which has reached theventilating passages 18 a and 18 c cools the outer peripheral side ofthe stator iron core 2 and flows from the ventilating passages 18 a and18 c to the cooler 28 a via the ventilating passage 21. The coolantcomponent which has reached the cooler 28 a is cooled by the cooler 28 aand flows from the cooler 28 a to the suction side of the fan 13 via aventilating passage 25.

[0076] The coolant component branched onto the ventilating passage 23side flows radially in the ventilating passage 23 to the ventilatingpassages 20 and 31, while cooling the end portion of the stator ironcore 2 and the coil end portions of the stator coils 4. The coolantcomponent which has reached the ventilating passage 20 flows axially inthe ventilating passage 20 to the cooler 28 c. The coolant componentwhich has reached the cooler 28 c is cooled by the cooler 28 c and flowsfrom the cooler 28 c to the ventilating passage 18 d. The coolantcomponent which has reached the ventilating passage 18 d cools the outerperipheral side of the stator iron core 2 and flows in the ventilatingpassage 18 d to the ventilating duct 5 communicating with theventilating passage 18 d.

[0077] The coolant component which has reached the ventilating duct 5communicating with the ventilating passage 18 d flows in the ventilatingduct 5 from the outer peripheral side to the inner peripheral side ofthe stator iron core 2, that is, to the air gap 6, while cooling theinside of the stator iron core 2 and the stator coils 4. The coolantcomponent which has reached the air gap 6 flows axially in the air gap 6to the ventilating ducts 5 communicating with the ventilating passages18 a and 18 c while cooling the inner peripheral side of the stator ironcore 2. The coolant component which has reached the ventilating ducts 5communicating with the ventilating passages 18 a and 18 c flows in theventilating ducts 5 together with the above-described coolant componentwhich has been branched from the discharge side of the fan 13 onto theair gap 6 side.

[0078] The coolant component which has reached the ventilating passage31 flows axially in the ventilating passage 31 to the cooler 28 b. Thecoolant component which has reached the cooler 28 b is cooled by thecooler 28 b and flows from the cooler 28 b to the ventilating passage 18b. The coolant component which has reached the ventilating passage 18 bcools the outer peripheral side of the stator iron core 2 and flows inthe ventilating passage 18 b to the ventilating duct 5 communicatingwith the ventilating passage 18 b.

[0079] The coolant component which has reached the ventilating duct 5communicating with the ventilating passage 18 b flows in the ventilatingduct 5 from the outer peripheral side to the inner peripheral side ofthe stator iron core 2, that is, to the air gap 6, while cooling theinside of the stator iron core 2 and the stator coils 4. The coolantcomponent which has reached the air gap 6 flows axially in the air gap 6to the ventilating ducts 5 communicating with the ventilating passages18 a and 18 c, while cooling the inner peripheral side of the statoriron core 2. The coolant component which has reached the ventilatingducts 5 communicating with the ventilating passages 18 a and 18 c flowsin the ventilating ducts 5 together with the above-described coolantcomponent which has been branched from the discharge side of the fan 13onto the air gap 6 side.

[0080] According to this embodiment, part of the coolant cooled by thecooler 28 a (or 28 e) and boosted by the fan 13 is branched; and, thecoolant component thus branched is cooled by the cooler 28 c, beingintroduced to the ventilating passage 18 d positioned at the centralportion of the stator iron core 2, and is allowed to flow from the outerperipheral side to the inner peripheral side of the stator iron core 2.

[0081] Accordingly, it is possible to supply the coolant, which issufficiently cooled by the cooler, to the central portion of the statoriron core 2.

[0082] As a result, according to this embodiment, the central portion ofthe stator iron core 2, at which the temperature of the supplied coolanttends to become highest and the amount of the supplied coolant tends tobecome smallest, can be cooled by the coolant, which is sufficientlycooled by the cooler, so that it is possible to suppress local heatgeneration in the air gap 6, and hence to level the axial temperaturerise distribution in the generator.

[0083] (Fifth Embodiment)

[0084]FIG. 9 shows a configuration of a turbine generator according to afifth embodiment. This embodiment is an improvement over the firstembodiment, which is effective in the case where the axial length of astator iron core 2 becomes longer. In this embodiment, the axialinterval between two adjacent ventilating ducts 5 provided in the statoriron core 2 is set at a large value in a first ventilating circuit 29and is set at a small, value in each of second and third ventilatingcircuits 30 and 31, which are larger in ventilating distance and thermalload than the first ventilating circuit 29. The remainder of theconfiguration is the same as that of the first embodiment, andtherefore, a description thereof is omitted.

[0085] According to this embodiment, since the axial interval betweentwo adjacent ventilating ducts 5 differs among the ventilating circuits29, 30 and 31, it is possible to reduce the amount of coolant flowing inthe first ventilating circuit 29, which is close to the fan 13, andthereby shorten the ventilating distance and increase the amount ofcoolant flowing in each of the second and third ventilating circuits 30and 31, which are more distant from a fan 13 and thereby longer inventilating distance, and hence to improve the effect of cooling thecentral portion of the stator iron core 2 and its neighborhood.

[0086] Further, in this embodiment, since the axial interval between twoadjacent ventilating ducts 5 differs among the ventilating circuits, itis possible to increase the cooling area of the central portion of thestator iron core 2 and its neighborhood by reducing the exposed area ofthe stator iron core 2 and stator coils 4 in the first ventilatingcircuit 29, which has a small thermal load, and by increasing theexposed area of the stator iron core 2 and the stator coils 4 in each ofthe second and third ventilating circuits 20 and 31, which have a largeventilating distance and thermal load, and hence to further improve theeffect of cooling the central portion of the stator iron core 2 and itsneighborhood.

[0087] It should be noted that this embodiment has been described as animprovement over the first embodiment however, the configuration of thisembodiment may be applied to the other embodiments as well.

[0088] (Sixth Embodiment)

[0089] FIGS. 10 to 12 show a configuration of a turbine generatoraccording to a sixth embodiment. This embodiment is a variation of thefirst embodiment, in which the coolers 28 and the ventilating passages20 and 21 provided in the lower portion of the generator in the firstembodiment are provided in both a front portion (front surface side) anda rear portion (back surface side) of the generator. The coolers placedin the vertical direction are aligned in a row in the axial direction onthe front and back surfaces of the generator in such a manner as toproject therefrom.

[0090] A cooler 28 a provided in a ventilating passage 18 a, a cooler 28c provided in a ventilating passage 18 c, a cooler 28 e provided in aventilating passage 18 e, and a cooler 28 g provided in a ventilatingpassage 18 g are arranged on the front portion of the generator in sucha manner as to be right-left symmetrical with respect to a center line14. A ventilating passage 21 communicating with the ventilating passages18 a, 18 c, 18 e, and 18 g is provided in the front portion of thegenerator.

[0091] A cooler 28 b provided in a ventilating passage 18 b, a cooler 28d provided in a ventilating passage 18 d, and a cooler 28 f provided ina ventilating passage 18 f are arranged on the rear portion of thegenerator in such a manner as to be right-left symmetrical with respectto the center line 14. A ventilating passage 20 communicating with theventilating passages 18 b, 18 d, and 18 e is provided in the frontportion of the generator. The remainder of the configuration is the sameas that of the first embodiment, and therefore, a description thereof isomitted.

[0092] According to this embodiment, the coolers 28 a, 28 c, 28 e, and28 g are arranged on one side (front portion of the generator) of aspace between a stator frame 1 and a stator iron core 2, which areopposed to each other with respect to a rotating shaft 9, and thecoolers 28 b, 28 d, and 28 f are arranged on the other side (rearportion of the generator) of the space. Accordingly, in the first,second, and third ventilating circuits 29, 30 and 31, a region in whicha coolant flows from the inner peripheral side to the outer peripheralside of the stator iron core 2 and then passes through the coolers 28can be formed in the front portion of the generator, and a region inwhich the coolant passes through the coolers 28 and then flows from theouter peripheral side to the inner peripheral side of the stator ironcore 2 can be formed in the rear portion of the generator. As a result,it is possible to eliminate the intersection of the ventilating passagesin which the coolant flows, and hence to reduce the ventilatingresistance of the coolant. This makes it possible to increase the amountof the coolant to be supplied to the central portion of the stator ironcore 2 and its neighborhood, and hence to further improve the effect ofcooling the central portion of the stator iron core 2.

[0093] In this embodiment, description has been made by way of theexample in which the coolers are arranged in both the front and rearportions of the generator; however, the same effect can be obtained evenby adopting an example in which the coolers are arranged in both theupper and lower portions of the generator.

[0094] (Seventh Embodiment)

[0095]FIG. 13 shows a configuration of a turbine generator according toa seventh embodiment. The turbine generator in this embodiment is of anopen-type in which the inside of the generator is cooled by atmosphericair sucked in the generator. In the figure, reference numeral 50designates a stator frame. A cylindrical stator iron core 51 is providedinside the stator frame 50. A plurality of slots, which continuouslyextend in the axial direction, are formed in an inner peripheral portionof the stator iron core 51 in such a manner as to extend in theperipheral direction. Stator coils 52 are enclosed in the slots. Aplurality of ventilating ducts 53, which continuously extend in theradial direction, are formed in the stator iron core 51 in such a manneras to be spaced from each other at equal intervals in the axialdirection.

[0096] A rotor iron core 55 is provided on the inner peripheral side ofthe stator iron core 51 with an air gap 54 disposed between the rotoriron core 55 and the stator iron core 51. A plurality of slots, whichcontinuously extend in the axial direction, are formed in an outerperipheral portion of the rotor iron core 55 in such a manner as toextend in the peripheral direction, and rotor coils are enclosed in theslots. Cylindrical retaining rings 56 for pressing both ends of therotor coils are provided at both ends of the rotor iron core 55. Arotating shaft 57 is provided integrally with the rotor iron core 55 insuch a manner as to extend in the axial direction along the central axisof the rotor iron core 55.

[0097] Annular end brackets 58 functioning as block members are providedat both axial ends of the stator frame 50. A bearing apparatus forrotatably supporting the rotating shaft 57 is provided on the innerperipheral side of each end bracket 58. A current collector forsupplying power to the rotor coils during rotation is provided at oneend (outside the bearing apparatus) of the rotating shaft 57. Aconnecting portion connected to a turbine serving as a driving source ofthe generator is formed at the other end (outside the bearing apparatus)of the rotating shaft 57.

[0098] Fans 59 for boosting a coolant sucked in the generator andcirculating it in the generator are provided at both ends (inside thebearing apparatuses) of the rotating shaft 57. While the fans 59 areused as the boosters for boosting the coolant in this embodiment, othertypes of boosters may be used. The fans 59 provided at both ends(outside the bearing apparatuses) of the rotating shaft 57 areright-left symmetrical with respect to a center line 60. The center line60 is a bisector which crosses the rotating shaft 57 at right angles atsuch a position as to equally divide the distance between the endbrackets 58 into two right-left symmetric parts.

[0099] An air suction hole 61 for sucking atmospheric air in thegenerator is provided on the inner peripheral side of each end bracket58 in such a manner as to face the fan 59. An air discharge hole 62 fordischarging the atmospheric air which has been sucked in the generatorto the outside of the generator is provided on the outer peripheral sideof each end bracket 58.

[0100] Ventilating passages 63 a to 63 g, which continuously extend inthe peripheral direction, are provided between the stator frame 50 andthe stator iron core 51 in parallel with each other in the axialdirection. The ventilating passages 63 a to 63 g are formed by aplurality of annular partition plates 64 for partitioning a spacebetween the stator frame 50 and the stator iron core 51 in the axialdirection, the inner surface of the stator frame 50, and the outerperipheral surface of the stator iron core 51, and are in communicationwith the ventilating ducts 53. The ventilating passages 63 a to 63 g areright-left symmetrical with respect to the center line 60.

[0101] Ventilating passages 65 and 66, which continuously extend in theradial direction, are provided between the stator iron core 51 and theend bracket 58. The ventilating passages 65 and 66 are right-leftsymmetrical with respect to the center line 60. Ventilating passages 67and 68, which provide communication between the air suction holes 61 andthe fans 59 and continuously extend in the axial direction, are providedbetween the end brackets 58 and the fans 59. The ventilating passages 67and 68 are formed by partitioning spaces between the stator iron core 51and the end brackets 58 by means of cylindrical partitioning plates 69,and are right-left symmetrical with respect to the center line 60.

[0102] A ventilating passage 70, which connects the ventilating passages65 and 66 to the ventilating passages 63 b, 63 d and 63 f andcontinuously extends in the axial direction, is provided in the lowerportion of the generator. A ventilating passage 71, which connects theair discharge holes 62 to the ventilating passages 63 a, 63 c, 63 e and63 g and continuously extends in the axial direction, is also providedin the lower portion of the generator.

[0103] Coolers 72 for cooling the coolant which has been sucked from theoutside of the generator are provided in the ventilating passages 63 b,63 d and 63 f. The coolers 72 a to 72 c are arranged in a lower portionof the generator in such a manner as to be aligned in a row in the axialdirection. It should be noted that the coolers 72 a to 72 c may bearranged in an upper portion of the generator. The coolers 72 a to 72 care right-left symmetrical with respect to the center line 60. A pipeline for supplying cooling water adit-a pipe line for discharging thecooling water are connected to each of the coolers 72 a to 72 c. Thecoolers 72 a to 72 c are identical to each other in terms of coolingcapacity.

[0104] A plurality of ventilating circuits including the above-describedventilating passages are formed in the generator. A first ventilatingcircuit 73, a second ventilating circuit 74, and a third ventilatingcircuit 75 are formed on one side (left side in FIG. 13) of the centerline 60, and, similarly, three ventilating circuits are formed on theother side (right side in FIG. 13) of the center line 60. The threeventilating circuits formed on the one side of the center line 60 areright-left symmetrical to the three ventilating circuits formed on theother side of the center line 60. Further, the flow of coolant and thetemperature rise characteristic on the one side of the center line 60are right-left symmetrical to those on the other side of the center line60. Therefore, the configuration of the ventilating circuits and theflow of coolant only on the one side of the center line 60 will bedescribed below.

[0105] The first ventilating circuit 73 is an open loop shown by a solidarrow in FIG. 13, which extends from the air suction hole 61 to the fan59 via the ventilating passage 67, and further extends from the fan 59to the air discharge hole 62 via the air gap 54, ventilating duct 53,ventilating passage 63 a, and ventilating passage 71.

[0106] The second ventilating circuit 74 is an open loop shown by adotted arrow in FIG. 13, which extends from the air suction hole 61 tothe fan 59 via the ventilating passage 67, further extending from thefan 59 to the cooler 72 a via the ventilating passages 65 and 70, andthen extends from the cooler 72 a to the air discharge hole 62 via theventilating passage 63 b, ventilating duct 53, air gap 54, ventilatingduct 53, and ventilating passages 63 c and 71.

[0107] The third ventilating circuit 75 is an open loop shown by adotted arrow in FIG. 13, which extends from the air suction hole 61 tothe fan 59 via the ventilating passage 67, further extending from thefan 59 to the cooler 72 b via the ventilating passages 65 and 70, andthen extends from the cooler 72 b to the air discharge hole 62 via theventilating passage 63 d, ventilating duct 53, air gap 54, ventilatingduct 53, and ventilating passages 63 c and 71.

[0108] The flow of coolant will be described below. First, atmosphericair, which is sucked from the air suction hole 61 into the generator byrotation of the fan 59, reaches the air suction side of the fan 59 viathe ventilating passage 67. The atmospheric air is boosted by the fan59, and is allowed to flow from the discharge side of the fan 59 torespective ventilating circuits.

[0109] In the first ventilating circuit 73, the atmospheric air boostedby the fan 59 flows axially in the air gap 54 to the ventilating duct 53communicating with the ventilating passage 63 a while cooling the innerperipheral side of the stator iron core 51. The atmospheric air whichhas reached the ventilating duct 53 communicating with the ventilatingpassage 63 a flows in the ventilating duct 53 from the inner peripheralside to the outer peripheral side of the stator iron core 51, that is,to the ventilating passage 63 a, while cooling the inside of the statoriron core 51 and the stator coils 52.

[0110] The atmospheric air which has reached the ventilating passage 18a cools the outer peripheral side of the stator iron core 51 and flowsfrom the ventilating passage 18 a to the air discharge hole 62 via theventilating passage 71.

[0111] In the second ventilating circuit 74, the atmospheric air boostedby the fan 59 flows radially in the ventilating passage 65 to theventilating passage 70, while cooling the end portion of the stator ironcore 51 and the coil end portions of the stator coils 52. Theatmospheric air which has reached the ventilating passage 70 flowsaxially in the ventilating passage 70 to the cooler 72 a. Theatmospheric air which has reached the cooler 72 a is cooled by thecooler 72 a and flows in the ventilating passage 63 b in the peripheraldirection, while cooling the outer peripheral side of the stator ironcore 51, and reaches the ventilating duct 53 communicating with theventilating passage 63 b.

[0112] The atmospheric air which has reached the ventilating duct 53communicating with the ventilating passage 63 b flows in the ventilatingduct 53 from the outer peripheral side to the inner peripheral side ofthe stator iron core 51, that is, to the air gap 54, while cooling theinside of the stator iron core 51 and the stator coils 52. Theatmospheric air which has reached the air gap 54 flows axially in theair gap 54 to the ventilating duct 53 communicating with the ventilatingpassage 63 c, while cooling the inner peripheral side of the stator ironcore 51.

[0113] The atmospheric air having reached the ventilating duct 53communicating with the ventilating passage 63 c flows in the ventilatingduct 53 from the inner peripheral side to the outer peripheral side ofthe stator iron core 51, that is, to the ventilating passage 63 c, whilecooling the inside of the stator iron core 51 and the stator coils 52.The atmospheric air which has reached the ventilating passage 63 c coolsthe outer peripheral side of the stator iron core 51 and flows from theventilating passage 63 c to the air discharge hole 62 via theventilating passage 71.

[0114] In the third ventilating circuit 75, the atmospheric air boostedby the fan 59 flows in the ventilating passage 65 to the ventilatingpassage 70 while cooling the end portion of the stator iron core 51 andthe coil end portions of the stator coils 52. The atmospheric air whichhas reached the ventilating passage 70 flows axially in the ventilatingpassage 70 to the cooler 72 b. The atmospheric air which has reached thecooler 72 b is cooled by the cooler 72 b and flows in the ventilatingpassage 63 d in the peripheral direction, while cooling the outerperipheral side of the stator iron core 51 and reaches the ventilatingduct 53 communicating with the ventilating passage 63 d.

[0115] The atmospheric air which has reached the ventilating duct 53communicating with the ventilating passage 63 d flows in the ventilatingduct 53 from the outer peripheral side to the inner peripheral side ofthe stator iron core 51, that is, to the air gap 54, while cooling theinside of the stator iron core 51 and the stator coils 52. Theatmospheric air which has reached the air gap 54 flows axially in theair gap 54 to the ventilating duct 53 communicating with to theventilating passage 63 c, while cooling the inner peripheral side of thestator iron core 51.

[0116] The atmospheric air which has reached the ventilating duct 53communicating with the ventilating passage 63 c flows in the ventilatingduct 53 from the inner peripheral side to the outer peripheral side ofthe stator iron core 51, that is, to the ventilating passage 63 c, whilecooling the inside of the stator iron core 51 and the stator coils 52.The atmospheric air which has reached the ventilating passage 63 c coolsthe outer peripheral side of the stator iron core 51 and flows from theventilating passage 63 c to the air discharge hole 62 via theventilating passage 71.

[0117] According to the embodiment configured as described above, theatmospheric air sucked from the outside of the generator and boosted bythe fan 59 is introduced to the ventilating passage 63 d positioned atthe central portion of the stator iron core 51, being cooled by thecooler 72 b, and is allowed to flow from the outer peripheral side tothe inner peripheral side of the stator iron core 51, so that it ispossible to supply the atmospheric air, which is sufficiently cooled, tothe central portion of the stator iron core 51.

[0118] Accordingly, the central portion of the stator iron core 51, atwhich the temperature of the supplied atmospheric air tends to becomehighest and the amount of the supplied atmospheric air tends to becomesmallest, can be cooled by the atmospheric air, which is sufficientlycooled by the cooler, and thereby, local heat generation in the air gap54 can be suppressed. This makes it possible to level the axialtemperature rise distribution in the generator and hence to suppress thethermal oscillation stroke of the rotor.

[0119] (Eighth Embodiment)

[0120]FIG. 14 shows a configuration of a turbine generator according toan eighth embodiment. This embodiment is a variation of the seventhembodiment. The turbine generator in this embodiment is of an open typelike the seventh embodiment. In this embodiment, coolers 72 a and 72 bare provided at both ends of a ventilating passage 70 in such a manneras to be right-left symmetrical with respect to a center line 60. Theremainder of the configuration is the same as that of the seventhembodiment, and therefore, a description thereof is omitted.

[0121] Even in this embodiment, the same effect can be obtained byproviding the same ventilating circuits and flow of atmospheric air asthose in the seventh embodiment, and further, since the number of thecoolers is reduced by one, it is possible to simplify the configurationof the generator and hence to reduce the cost of the generator.

[0122] The present invention is applicable to a rotating electricmachine in which coolers for cooling a coolant such as air or hydrogengas are provided. In particular, the present invention is applicable toa rotating electric machine using air as a coolant, that is, anair-cooled generator, and provides an increase in the capacity of agenerator, for example, of a hydrogen-cooled type.

What is claimed is:
 1. A rotating electric machine comprising: aplurality of ventilating passages formed between a stator frame and astator iron core; a cooler which cools a coolant is provided at least inone ventilating passage, communicating with a central portion of saidstator iron core, of said plurality of ventilating passages; and aventilating circuit in which the coolant cooled by said cooler isallowed to flow to said central portion of said stator iron core in adirection from an outer peripheral side to an inner peripheral side ofsaid stator iron core via said at least one ventilating passage whichcommunicates with said central portion of said stator iron core.
 2. Arotating electric machine according to claim 1, further comprising abooster for boosting the coolant, the ventilating circuit enabling flowof the coolant which is boosted by the booster and cooled by saidcooler.
 3. A rotating electric machine according to claim 1, wherein thebooster includes a fan.
 4. A rotating electric machine comprising: aplurality of ventilating passages formed between a stator frame and astator iron core; coolers which cool a coolant being provided in saidplurality of said ventilating passages; a ventilating circuit in whichat least a portion of the coolant which is cooled by one of said coolersis further cooled by another of said coolers, and is allowed to flow toa central portion in an axial direction of said stator iron core in adirection from an outer peripheral side to an inner peripheral side ofsaid stator iron core at least via one ventilating passage of saidplurality of ventilating passage which communicates with said centralportion in an axial direction of said stator iron core.
 5. A rotatingelectric machine according to claim 4, further comprising a booster forboosting the coolant, the ventilating circuit enabling flow of thecoolant which is boosted by the booster and cooled by said cooler.
 6. Arotating electric machine according to claim 4, wherein the boosterincludes a fan.